WO 99/66466 discloses a method and device for remote detection of objects. Each object is provided with a tag including at least two microfibers arranged at an angle in relation to each other. The angle or angles provide an indication of the identity of the tag and, thus, the identity of the object or article to which it is attached. The microfibers are exposed to a magnetic modulation field having a DC component and an AC component, which influences on the high frequency impedance of the microfiber. The varying impedance modulates a high frequency electromagnetic signal, such as a microwave signal, directed towards the microfiber and the reply signal is modulated by the frequency of said AC component. A second magnetic field is superimposed on said first modulation field. The direction and amplitude of the second magnetic field is adjusted so that the composite magnetic field in the direction of the microfiber is zero, which results in that the AC component of the reply signal of the microwave is effectively doubled. In this way, the direction of the microfiber in relation to the magnetic fields can be calculated.
This method of remote determination of an angular position of several microfibers operates well if the plane of the tag comprising the microfibers is substantially parallel with a reference plane, which is perpendicular to the microwaves and substantially parallel to the magnetic field. However, if the tag is inclined in relation to such a reference plane, the angles become distorted. Moreover, certain angular positions of the microfiber will not produce any reply, which is especially true if the microfiber is perpendicular to the first modulation field.